Aluminum base alloy diecasting composition

ABSTRACT

AN ALUMINUM BASE ALLOY AND AN AUTOMOBILE WHEEL DIECAST THEREFROM, THE ALLOY CONSISTING ESSENTIALLY OF ALUMINUM AND BY WEIGHT PERCENTAGE OF THE TOTAL COMPOSITION, MAGNESIUM 0.25 TO 0.6%, COPPER 0.25 TO 0.6%, IRON 0.5 TO 1.5%, SILICON 11 TO 13.5% CHROMIUM 0.25 TO 0.4%,   A MAXIMUM OF 3% ZINC, A MAXIMUM OF 0.5% MANGANESE AND A MAXIMUM OF 0.2% OF EACH OF ITANIUM, NICKEL, TIN AND LEAD.

April 10, 1973 R, s, LINDBERG ET AL 3,726,672

ALUMINUM BASE ALLOY DIECASTING COMPOSITION Filed Oct. 50. 1970 /NVENTO/?5 Qzc/zardSLz'Izdberg yggig/lziarmsim) United States Patent 3,726,672 ALUMINUM BASE ALLOY DIECASTIN COMPOSITION Richard S. Lindberg, Homewood, and G. Leslie Armstrong, Crete, Ill., assignors to US. Reduction C0.

3,726,672 Patented Apr. 10, 1973 to 0.6% copper; 0.5 to 1.5% iron; 11 to 13.5% silicon; and 0.25 to 0.4% chromium. The high silicon content and the copper content substantially contribute, we believe, in combination with the other ingredients to the superior physical properties of this alloy.

Filed Oct 30, 1970 Sen 85,372 The composition of this invention which maximizes the 1m, czz 21 02 characteristics and properties of die-cast products, such US. Cl. 75-142 2 Claims as automobile wheels, while minimizing the costs attendant the manufacture and use of the alloy composition,

URE consists essentially of aluminum, and by weight of the ABS CT OF THE DISCLOS final alloy, 025 to 0.6% magnesium, 0.25 to 0.6% cop- An aluminum base ll y and an mobile wh el dieper, 0.5 to 1.5% iron, 11 to 13.5% silicon, 0.25 to 0.4% cast therefrom, the alloy consisting essentially of alumih i a maximum of 3% zinc, a maximum of 0.5% Hum and y Weight Percentage of the total comlfositiofl, manganese, and a maximum of 0.2% each of titanium, magne$il1m Q to 05%, pp to (16%, Iron nickel, tin and lead. Die-cast products such as automobile SIIICOII 11 t 13-5%, Ch1'0m111m i0 15 wheels cast of this alloy have an overall combination of a maXlIIluII} 0f 3% Zinc, a maXlIIlllm impact strength, fatigue strength, tensile strength, yield and a maxlmum 0f 01% 0f each of tltamllm, nlckel, 1111 strength and ductility characteristics which is superior to and leadthose of other aluminum base diecasting compositions of which we are aware, including those characteristics avail- This invention relates to an aluminum base alloy havable in products die-cast from 364 alloy. Furthermore, ing high strength, excellent diecasting characteristics, exthe corrosion resistance and machineability of wheels d1ecellent machinability and superior mechanical properties. cast of this alloy are quite excellent and the diecasting It is especially useful for the diecasting of automobile characteristics are as good as any aluminum alloy availwheels, although its application is not so limited. able for the high stress applications for which the alloy With the advent of a keen interest in the use of lightof this invention is useful. weight aluminum base alloys for articles which must stand Although the advantages of this invention may be ohthe abuse and stresses heretofore reserved for ferrous tained within the aforementioned ranges, we have determetals and alloys, it became important to develop immined that an especially useful preferred range of ngreproved aluminum base alloys for such products. Howclients is a composition consisting essentalg of (alrnmum, ever, to be maximally useful for automobile wheels and and by weight of the final composition to 0 magother such products, aluminum base alloys had to be dienesium, 0.25 to 0.5% copper, 0.4 to 0.8% iron, 11 to castable, corrosion resistant, readily machinable and of 12% silicon, 0.3 to 0.4% chromium, a maximum of 1% a higher strength than those aluminum base alloys prezinc, a maximum of 0.35% manganese, a maximum of viously available and at a lower cost than other available 0.05% of each of titanium and nickel, and a maximum alloys having comparable properties. of 0.1% of each of tin and lead.

Although aluminum base die-cast alloys have been on FIGS. 1 and 2 illustrate typical automobile wheels the market for many years where lightweight, accurate which have been die-cast with aluminum base alloys. dimensioning and the like was important, generally those Die-cast automobile wheels have been made from alualloys were not suitable for use in applications where subminum base alloys of this invention, as well as from a fil i lf 1 h t d 40 commercially iivaiabled364 alloy.h Sevgrall such wheels 6 011 Y a y W 10 met W1 1m! 6 Success an have been ana yze to etermine t eir na composition. which has Properties generally Suitable g Stress Further, those wheels have been tested for yield strength, applications, such as in die-cast automobile wheels, is one t il strength and ductility. known to the trade as 364 alloy. This is made generally Spoke wheels 10 die-cast generally in the configuration i accordance With Blackmllll ,3 3, of FIG. 1 were analyzed and were found to have the folthough that alloy improved p Prior art alloys in lowing compositions (the remainder being aluminum):

Mg Cu Fe Zn Si Mn Ti Ni Cr Sn Pb Be 364alloy .25 .07 .51 .04 8.63 .01 .01 .01 .39 .02 .01 .0053 Aalloy ,32 .32 .57 .29 11.04 .17 .03 .01 .40 .01 .01 0

tain respects, the properties of that alloy were not as good Test bars Were cut from those wheels and flange 12 as wlas gefsirable. Furthermore, the cost of that alloy was test bars, spider 14 test bars, and rim 16 test bars were too ig genera 115eq y, insofar as alllIIli' tested for yield strength, for tensile stren th, and for num base alloy die-cast automobile wheels were concerned, percent elongation with the f ll i results? that alloy was used only for high cost specialty wheels.

In accordance with this invention an aluminum base die-casting alloy having substantially improved mechanical Flange Spider Rim properties is provided. Its cost is substantially lower than A 364 A 304 A 354 the cost of 364 alloy prevlfmsly used for slmlar Yield strength (p.s.i.) 18,400 15,000 20,500 10,100 21,700 19, 200 poses, and indeed scrap aluminum and other secondary Tenslle strength (p.s.1.).. 25,500 20,300 23, 000 28,000 20,000 27,400 aluminum available for secondary reformulation, rather Percent elongatwn 2% 1% 5 3% 2 21/5 than primary aluminum, may be used to compound the *ofiset equals 0.2 percent. alloy of this invention. As such, the alloy of this invention provides the commercial otential, f th fi t ti f In these charactenstics wheels dle-cast from an alloy the substitution of aluminum base alloy automobile wheels A of this invention were essentiall equal to or substanfor steel wheels on a much larger scale. tially better than those die-cast from 364 alloy, and at a As its essential in redients, th diecasting l i substantially lesser overall cost. The machinability, the

base alloy of this invention comprises aluminum, and by weight of the final alloy, 0.25 to 0.6% magnesium; 0.25

diecasting characteristics and the corrosion resistance of the alloy A of this invention also were all at least as good as, and in some instances substantially better than those of the 364 alloy.

Deep dish wheels 20 die-cast generally in the configuration illustrated in FIG. 2 were also tested for their yield strength, tensile strength and percent elongation. Test bars cut from flanges 22, rims 24 and spiders 26 from alloys B falling within the preferred range of this invention identified above and from a commercially available 364 alloy had the following properties:

nium, nickel, tin and lead and the balance aluminum.

2. An aluminum base diecasting alloy composition consisting essentially of aluminum and by weight percentage of the total composition, magnesium 0.25 to 0.4%, copper 0.25 to 0.5%, iron 0.4 to 0.8%, silicon 11 to 12%, chromium 0.3 to 0.4%, a maximum of 1% zinc, a maximum of 0.35% manganese, a maximum of 0.05% of each of titanium and nickel, a maximum of 0.1% of each of tin and lead and the balance aluminum.

Flange Spider Rim B 364-, B 364 B 364 Yield strength (p.s.i.)* 22, 000; 58, 300 16, 800 23, 300; 17, 900 17, 400 23, 400; 19, 700 19, 100 Tensile strength (p.s.i.). 23, 800; 25, 000 20, 700 29, 500; 27, 700 24, 700 25, 400; 24, 600 20, 000 Percent elongation 2%; 5 2% 3; 4 3% 3; 4

* Offset equals 0.2 percent.

These last tests from three die-cast wheels, two cast from alloys B of this invention and one cast from 364 20 alloy even more graphically illustrate the substantially improved characteristics and properties of the alloys of this invention as compared with those of the 36 4 alloy.

What is claimed is:

1. An aluminum base diecasting alloy composition con- 25 sisting essentially of aluminum and by weight percentage of the total composition, magnesium 0.25 to 0.6%, copper 0.25 to 0.6%, iron 0.5 to 1.5%, silicon 11 to 13.5%, chromium 0.25 to 0.4%, a maximum of 3% zinc, a maximum of 0.5% manganese, a maximum of 0.2% of each of tita- 30 References Cited UNITED STATES PATENTS 

